US2656307A

US2656307A - Conversion of hydrocarbon materials

Info

Publication number: US2656307A
Application number: US133026A
Authority: US
Inventors: Robert A Findlay
Original assignee: Phillips Petroleum Co
Current assignee: Phillips Petroleum Co
Priority date: 1949-12-15
Filing date: 1949-12-15
Publication date: 1953-10-20
Anticipated expiration: 1970-10-20

Description

Oct. 20, 1953 R. A. FINDLAY CONVERSION OF' HYDROCARBON MATERIALS Filed Dec. 15, 1949 A T TORNE V5 Patented Oct. 20, 1953 TENT oFFlcl:

CONVERSION 0F HYDRocARBoN MATERIALS Robert A. Findlay, Bartlesville, Okla., assignor to Phillips Petroleum Company, a corporation of Delaware Application December 15, i949, serial No. 133,026

11 Claims.

This invention relates to treating hydrocarbon materials. In one of its more specific aspects it relates to a process for converting low-boiling normally gaseous hydrocarbon materials and higher boiling normally liquid hydrocarbon materials.` In another of its more specic aspects this invention relates to a combination thermal conversion process for Iconverting low-boiling normally gaseous parainic hydrocarbons, such as methane, ethane, propane and butanes, and high-boiling normally liquid hydrocarbon materials, such as gas oils, fuel oils and crude residuum. In still another of its more specic aspects this invention relates to a combination thermal conversion process and an eiiluent separation process for thermally converting low-boiling normally gaseous hydrocarbon materials and higher boiling normally liquid hydrocarbon materals and separating desired products of such conversions from tar and coke formed during such conversions. y

It is old in the art to thermally convert lowboiling normally gaseous hydrocarbon materials, such as methane, ethane, propane, and butanes.

Also, it is old in the art to thermally convert normally liquid hydrocarbon materials, such as highboiling hydrocarbon fractions, such as gas oils, fuel oils and crude residuum. However, the petroleum industry is always striving to perform such thermal conversions more economically and 'more efficiently. It is advantageous to produce olefin hydrocarbons, such as ethylene, propylene and butylenes, which are used as starting mate- -rials in the synthesis of many hydrocarbon compounds as well as other organic compounds/ .Aromatic hydrocarbons and hydrocarbon-type materials normally have very good fuel ratings land theirl production is Sought after in petroleum conversion processes. New thermal conversion processes for the production of olefnic hydrocarbons and aromatics which are economical, eilicient and which give a high yield are valuable steps forward in the art.

I have invented a combination process for con--` verting low-boiling normally gaseous hydrocarbon materials and higher-boiling normally liquid hydrocarbon materials. In the process of my invention, low-boiling normally gaseous hydrocarbon materials are converted in a iirst con-v version zone.A The eflluent resulting from this first conversion is utilized in a second conversion zone to at least partially vaporize and convert higher boiling normally liquid hydrocarbon materials by directly transferring heat from the.

`55 perature cracking at relatively low pressures of @fllent from the rs't conversion operation to (Cl. ISG- 66) 'the higher boiling normally liquid hydrocarbon -materials. The resulting eluents from both conversion operations are withdrawn in admixture :With each other and subsequently treated to separate and recover the desired products resulting from these conversions.

I find that the process of my invention is parjticularly adaptable to the combination conversion of low-boiling normally gaseous hydrocarbon materials, such as methane, ethane, propane and/or butanes, and high-boiling normally liq- 'f uid hydrocarbon materials, such as gas oils, fuel foils and crude residuum. In the conversion operation of the process of my invention, wherein D the higher honing nei-many liquid hydrocarbon "materials are converted, I prefer to use a very fadvantageous and unique atomizing operation, that is, the eflluent from the conversion of the low-boiling normally gaseous hydrocarbon ma- Eoterials is directly contacted with the high-boil- A averted During the atomizing operation the ef- 5' mally liquid hydrocarbon materials. Subsequent to the second conversion operation in which the i high-boiling normally liquid hydrocarbon materials are converted, the mixed eflluent resulting from both conversion operations is quenched to a temperature below the conversion temperature of the high-boiling normally liquid hydrocarbon t materials, and the resulting quenched effluent is treated to remove tars and coke formed 4during the conversion operations. For removing such tars and coke I find it desirable to employ a centrifugal separation operation followed by a washing step, which is used to remove nely entrained coke particles. Aromatics are recovered from the wash oil used to remove the ne coke 50' particles and resulting products from the washing operation are separated and recovered in conventional separation means, if desired.`

I nd that the process of my invention is very economical and efficient. Relatively high-temboth low-boiling normally gaseous hydrocarbon materials and heavy hydrocarbon oils produces large quantities of olefins, such as ethylene and propylene, and aromatics, and in the process oi my invention I nd that the heavy oil cracking or conversion is obtained substantially Without cost, since the effluent from the low-boiling normally gaseous hydrocarbon material conversion is quenched with heavy oils which are thereby converted. Since quenching is necessary in al1 cases, the heat recovery scheme. of the process of my invention is very advantageous, Relatively large amounts of heavy oils can be processed at very low cost. In addition, the atomizng procedure used on the high-boiling hydrocarbons in the process of my invention is found to be very advantageous in that tars and coke which are formed are kept in fluid -state thus making their removal relatively easy in the separation procedure of my process.

It is an object of this invention to provide a method for the treatment of hydrocarbon materials.

It is another object of this invention to provide a combination thermal conversion process for the conversion of low-boiling normally gaseous hydrocarbon materials, such as methane, ethane, propane and butanes, and higher boiling nor.. mally liquid hydrocarbon materials, preferably high-boiling hydrocarbon materials, such as gas oils, fuel oils and crude residuum.

It is another object of this invention to provide a combination thermal conversion and separation process for the conversion of low-boiling normally gaseous hydrocarbon-materials, such as methane, ethane, propane and butanes, and higher boiling normally liquid hydrocarbon materials, preferably high-boiling hydrocarbon materials, such as gas oil, fuel oils and cruderesiduum, and the separation of tars and coke from desired products formed during such conversion.

It is a further object of this invention to pro.. vide a very eicient and economical combination thermal conversion process for performing the above-nentioned thermal conversions and for removing tars and coke from the eluent resulting from such conversions.

Other objects and advantages of the process of my invention will become apparent, to one skilled in the art, upon reading this disclosure.

The drawings which accompany and are a part of this disclosure diagrammatically set forth a preferred specific embodiment of the process of my invention. Figure l depicts a flow scheme to show how the process of my invention is carried on and includes a preferred means of separating tars and coke formed during the conversions from the combined effluent resulting from both conversion operations. Figure 2 diagrammatically depicts a combination atomizing and soaking zone unit which I find suitable for carrying on the atomizing step of the process of my invention and the conversion of high-boiling normally liquid hydrocarbon materials.

The process of my invention can be used to convert low-boiling normally gaseous hydrocarbon materials and higher boiling normally liquid hydrocarbon materials in a single combination process. Effluent from a low-boiling normally gaseous hydrocarbon conversion process which contains heat is used to directly furnish heat to higher boilingV normally liquid hydrocarbons to heat-them to conversion temperature. As a result of this heat exchange, the effluent from the version process is cooled to a temperature below its conversion temperature. Some examples of low-boiling normally gaseous hydrocarbons Which can be converted or cracked in the process of my invention and which are preferred are paraffinic hydrocarbons having from 1 to 4 carbon atoms per molecule such as methane, ethane, propane and butanes, Ethane and/or propane can readily be converted to ethylene at high temperature, low pressure and short contact time, and prop-ane can readily be converted to ethylene and propylene at high temperature, low pressure and short contact time. Methane conversion to produce hydrogen athigh temperature, low pressure and short contact time is readily accomplished. These conversion operations give particularly advantageous results when used in the combination process of my invention. The process of my invention can be used to convert normally liquid hydrocarbons, l,generally C5 and higher boiling hydrocarbons, preferably light gas oils and highboiling hydrocarbon materials, such as heavy gas oils, fuel oils, crude residuum, and the like. I nd that heavy gas oil, fuel oil and crude residuum give particularly good results when converted or cracked in the normally liquid hydrocarbon conversion step of the combination process of my invention. Oleiins, particularly ethylene, and aromatics production are particularly good when ethane and/or propane are converted and used to partially Vaporize, atomize, and convert heavy gas oils, fuel oils or crude residuum by the method of the process of my invention.

Referring now to Figure 1, which diagrammatically sets forth a preferred specific embodiment of the process of my invention, the following discussion is directed at my combination of thermal conversion processes for converting methane. ethane and/or propane, and a heavy oil, such as heavy gas oil, fuel oil or crude residuum. Also, a preferred separation scheme for removing tars and cokes formed during such conversions, from the combined eiiiuent resulting from such conversions is discussed. A methane, ethane and/or propane stream is passed via line 3 into cracking zone 5 wherein the light paraffnic hydrocarbon stream is thermally converted at a relatively high temperature, a relatively low pressure and for a relatively short contact time. Cracking zone 5 can be any suitable thermal conversion process, but it is preferably a thermal conversion process carried out by utilizing pebble heater apparatus, that is, pebble heater apparatus utilizing a contiguous moving bed of refractory pebbles. Normally, the refractory pebbles are heated in a pebble heating zone and flow by gravity into the thermal conversion zone wherein they heat the light parafnic hydrocarbon stream to conversion temperature.

The effluent resulting from the thermal conversion carried on in cracking zone 5 is Withdrawn via line 7 and is passed into an atomizing zone 9. In atomizing zone 9 the hot effluent from cracking zone 5 is directly contacted with heavy oil passed into atomizing zone 9 via line il, thereby partially vaporizing the heavy oil and atomizing the remainder. Atomizing zone 9 can be any suitable device that is so designed to bring the heavy oil into direct contact with the hot eiiiuent from cracking Vzone 5. I prefer to use a Venturi section, forcing the heavy oil into the gas stream as it passes through the Venturi throat. Figure 2, which is discussed hereinafter,

low-boiling normally gaseous hydrocarbon con- .'(5 depicts a preferred Venturi atomizing zone which 5 exhausts directly into a soaking chamber wherein the heated heavy oils, in vapor and atomized form, are Aheld for the desired length of time prior to quenching so that thermal conversion of the heavy oils can proceed to the desired degree of completion.

Resulting vapors and atomized heavy oils are withdrawn from atomizing zone 9 via line I3 and passed into soaking zone I5, which can be any suitable chamber or series of chambers for holding the heavy oils at conversion temperature for a desired length of time.

As the result of contacting the effluent from cracking zone 5 and the heavy oil in atomizing Zone 9, the efiiuent from cracking zone 5 is cooled t a point below its conversion temperature and theheavy oils are heated to conversion temperature. I find it desirable to control the temperature by regulating the amount of heavy oils passed into atomizing zone 9.

The mixture resulting from both conversions is withdrawn from soaking zone via line Il, quenched in a suitable manner, preferably by directly contacting the combined effluent with a quenching medium introduced via line I9, and a resulting mixture is passed into separation zone 2|. vThe effluent mixture from the conversion which has been quenched can be Withdrawn, if desired, via kline 23 for treatment and suitable separation means. aration process which I have depicted in Figure l is very satisfactory for the desired separation process. I prefer that separation zone 2| be a centrifugal separator. The combined quenched eiiiuent is passed tangentially into centrifugal separation zone 2|. Centrifugal force throws the greater quantity of the tar and coke formed during the thermal conversionV operations to the walls of the centrifugal separator. The tar and coke remain in fluid state because I keep the walls at a temperature high enough to prevent the tars and cokes from setting up. Resulting separated tar and coke are withdrawn from the bottom portion of the centrifugal separator via line 25.

'A resulting stream from which the greater portion of tar and coke has been removed is withdrawn from separation zone 2| via line 21 and is passed into a washing zone 29 which can conveniently be a bubble-tray or packed Wash column. Within washing zone 29 the said resulting stream is contacted with a circulating wash oil stream. The wash oil stream is compatible with ine coke particles which pass through the centrifugal separator, washing the ne coke particles and removing them from the desired effluents of the thermal conversion processes. `Resulting products of the thermal conversionprocesses.are withdrawn from washing zone 29 via line 3| and are passed to conventional separation means wherein'the products are separated and recovered as desired.

Wash oil containing fine coke particles removed in washing zone 29 is withdrawn via line 33 and is passed intoA separation Zone 35, preferably a settling zone, wherein the fine coke particles are removed from the wash oil and are withdrawn via line 3l. Resulting wash oil is removed from sep- However, I find that the sepv aration Zone 35 via line 59 andis passed into heat p exchange zone lllV wherein it is cooled prior to ventional fractionation equipment Vbeing desired, toseparate and recover aromatics.` A portion of the wash oil from heat. exchange zone 4|, with make-up wash oil introduced via line 45, is recir- The resulting vapors and atomized heavy oils are discharged directly into a soaking chamber wherein a conversion of the heavy oil takes place. The venturi is formed of a suitable ceramic material, such as heat resistant fired clays, or it can Y be formed of known heat resistant metallic alloys. The soaking chamber is preferably lined with heatresistant material, such as insulcrete or the like materials, since the combined stream is maintained at relatively high temperatures.

The soaking chamber is so designed that the heavy oils are held at conversion temperature` Vfor a desired length ofV time `and the combined efiiuent resulting from the conversions is Withdrawn from the soaking chamber as indicated by arrow 53. Rapid quenching, as discussed `hereinbefore, is carried out followingthe heavy oil conversion in the soaking chamber.

In the process of my invention I prefer to carry on ethane or methane cracking, or methane and ethane cracking, at a pressure of from 5 to 40, preferably 5 to 25, pounds per square inch absolute, a temperature of from 1300-2500 F., preferably 1500-2000 F., and for a contact time of fr crn0-00l to l second, preferably 0.05 to 0.2 second. If propane, or propane and ethane are converted in carrying out the process of my invention, I prefer to carry on such conversions at a pressure of from 5 to 40, preferably 5 to 25, pounds per square ,inch absolute, at a. temperature of from l200-2400 F., preferably 1400-l900 F., and for a contact time of from 0.002 to 1.5 seconds, preferably 0.07 to 0.5 second. In the heavy oil conversionstep of the process of my invention, I `prefer to carry on the heavy gas oil, fuel oil, or crude residuum conversion at a pressure of from 5 to 40, preferably 5 to 25 pounds per square inch absolute, at a temperature of from 950-1450" the wall temperature in centrifugal separation zone 2| at the temperature at which the com-` bined conversion eiliuents are quenched, is suitable to maintain the tars and coke in fluid state ,Within the centrifugal separator so that they will not set up on the walls.

In the washing operation performed in Washing zone 29, I prefer to use a liquid washing medium, such as a mineral seal OiLalight gas oil or the like. Steam or Water can beused, if desired, as the quenching medium. However, I prefer to use a thermally stable quench oil, such as a cycle oil from a product fractionator employed in the conventional separation means used to separate and recover the products resulting from the conversions,, for instance, a fairlyr refractory cycle oilsliatvingfgo exampie* a boi 5G60 AA quenchoiLif stream, is desirably ja notrtoolow a boiinfg` range'to result-in substantial vaporizatiorr rof #tha-quench -oil'.

It is to be understood-thatthel above set forth preferredespecio"direction-ofmyinvention, settingfwrth 'materia1s,- such asfeed streams to the conversionpperation, quenching mediums,y Wash oils'fetcf,stemperatures; pressures-,'etc., is not to unduiyiirnitrthel'scope of -myinvention." I

Foiiovvingfis an-exampie of the process of my invention.`l The: ioiiowing-exampleis carried out njthemarl 1' @IMM Ookeiormed ner depicted bythe-diagrammatic fiovv- Cen I find that by decreasing'the heavy oil feed rate,

largerl amounts of '-olefinic- @hydrocarbons-and" 'f smaller amounts of iiqiiidproductsy are produced# skilled vvin the art', -1 various modications-=of Athis' invention- Ycan 'bek made, or o11ovved,'-in theiight of this disc1osure=- without departing from the spirit and discussion, or scopefof this the claims:`

I claimt' l. A process disclosure kor from the scopeof crude'residuum and mixtnresgthereof which com: prises:- passing fethaner into a Vfor converting ethaneand liquid-11 high-boilinglhydrocarbon materialsselected from' the group consisting of heavy gas ^oi1-, v'fue1-ii,

v first conversion Z011@4 and-^i1f1ereinv thermaliyfconverting same4v at -a g b021500 F-ata pressure vmethane, ethane, propane and liquid mixtures thereof and high-boiling hydrocarbon materials selected from the group consisting of heavy gas oil, fuel oil, crude residuum and mixtures thereof, vwhich comprises: passing such a parafnic hydrocarbon into a rst conversion zone and therein thermally converting same at conversion temperature and pressure; withdrawing resulting products of conversion from said first conversion zone and passing same into an atomizing Zone; passing such a liquid high-boiling hydrocarbon material into said atomizing zone; directly contacting said resulting products of conversion from said first conversion zone and said liquid high-boiling hydrocarbon material in said atomizing zone, thereby vaporizing a portion, atomizing a remaining portion and heating to conversion temperature said high-boiling hydrocarbon material, and quenching said resulting products of conversion from said rst conversion zone below conversion temperature; directly passing a resulting mixture of vapors and atomized high-boiling hydrocarbon materials into a second conversion zone and therein thermally converting said high-boiling hydrocarbon materials at conversion temperature pressure; and withdrawing resulting vapors and atomized high-boiling hydrocarbon materials from said second conversion zone and directly contacting same with a quench medium, thereby quenching to a temperature below conversion temperature.

4. The process of claim 3 wherein said quench medium is water.

5. The process of claim 3 wherein said quench medium is a thermally stable quench oil.

6. A process for converting paraflinic hydro-- carbons selected from the group consisting of methane, ethane, propane and mixtures thereof and high-boiling hydrocarbon materials selected from the group consisting of heavy gas oil, fuel oil, crude residuum and mixtures thereof which comprises: passing such a paraflinic hydrocarbon into a rst conversion zone and therein thermally converting same at conversion temperature and pressure; withdrawing resulting products of conversion from said rst conversion zone and passing same into an atomizing Zone; passing such a high-boiling hydrocarbon material into said atomizing sone; directly contacting said resulting products of conversion from said first conversion zone and said high-boiling hydrocarbon material in said atomizing zone, thereby Vaporizing a portion, atomizing a remaining portion and heating to conversion temperature said highboiling hydrocarbon material, and quenching said resulting products of conversion from said nrst conversion zone below conversion temperature; passing a resulting mixture of vapors and atomized high-boiling hydrocarbon materials into a second conversion zone and therein thermally converting said high-boiling hydrocarbon materials at conversion temperature and pressure; withdrawing resulting vapors and atomized high-boiling `hydrocarbon materials from said second conversion zone, directly contacting same with a quench medium, thereby quenching to a temperature below conversion temperature but at least high enough so that tars and coke formed in said conversion remain in a fluid state; passing resulting quenched vapors and high-boiling hydrocarbon materials, containing said tars and coke in uid state, into a centrifugal separation zone and therein separating tars and coke from said vapors and high-boiling hydrocarbon materials; withdrawing resulting tars and coke from said centrifugal separation zone; withdrawing resulting vapors and high-boiling hydrocarbon materials, containing ne particles of coke, from said centrifugal separation zone, passing same into a washing zone and therein directly vand countercurrently contacting same with a wash oil, thereby wetting said fine coke particles and removing them from said resulting vapors and high-boiling hydrocarbon materials passed into said washing zone; withdrawing resulting wash oil from said washing zone, removing coke particles and aromatic hydrocarbons from same and recycling resulting wash oil to said washing zone; and withdrawing resulting overhead vapors from said washing zone.

.7. The process of claim 6 wherein said quench medium is a thermally stable quench oil, and said wash oil is a mineral seal oil.

8. The process of claim '7 wherein the said iirst conversion zone is a pebble heater.

9. A process according to claim 6 in which ethylene is produced and in which the conditions in the rst conversion zone are: a temperature in the range l300-2500 F., a pressure in the range 5 to 40 pounds per square inch absolute, and a contact time in the range 0.001 to 1 second and wherein the conditions in the second conversion zone are: a temperature in the range 950- 1450 F., a pressure in the range 5 to 40 pounds per square inch absolute, and a contact time in the range from 0.2 to 3.5 seconds, and wherein the eiluent vapors and atomized high boiling hydrocarbon materials from said second conversion zone are quenched to a temperature below approximately 900 F.

10. A process for converting low-boiling normally gaseous hydrocarbon materials and highboiling normally liquid hydrocarbon materials, which comprises: converting a low-boiling normally gaseous hydrocarbon material at conversion temperature and pressure in a rst thermal conversion operation; passing resulting products of said first thermal conversion into an atomizing zone, therein directly contacting same with such a high-boiling normally liquid hydrocarbon material which is passed into said atomizing zone, thereby vaporizing a portion, atomizing a remaining portion and heating to conversion temperature said high-boiling normally liquid hydrocarbon materials, and quenching said resulting products from said rst thermal conversion operation to a temperature below conversion temperature; directly converting resulting atomized and vaporized high-boiling normally liquid hydrocarbon material at conversion temperature and pressure while in admixture with said resulting products from said rst thermal conversion operation in a second thermal conversion operation; and quenching a resulting mixture of products of said rst and second thermal conversion operations to a temperature below conversion temperature.

11. A process for converting low-boiling normally gaseous hydrocarbon materials and a reduced crude, which comprises: passing said lowboiling normally gaseous hydrocarbon material into a rst conversion zone and therein converting same at conversion temperature and pres-

Claims

1. A PROCESS FOR CONVERTING ETHANE AND LIQUID HIGH-BOILING HYDROCARBON MATERIALS SELECTED FROM THE GROUP CONSISTING OF HEAVY GAS OIL, FUEL OIL, CRUDE RESIDUUM AND MIXTURES THEREOF, WHICH COMPRISES: PASSING ETHANE INTO A FIRST CONVERSION ZONE AND THEREIN THERMALLY CONVERTING SAME AT A TEMPERATURE OF FROM 1300 TO 2500* F., AT A PRESSURE OF FROM 5 TO 40 POUNDS PER SQUARE INCH ABSOLUTE AND AT A CONTACT TIME OF FROM 0.001 TO 1 SECOND: WITHDRAWING RESULTING PRODUCTS OF CONVERSION FROM SAID FIRST CONVERSION ZONE AND PASSING SAME INTO AN ATOMIZING ZONE; PASSING SUCH A LIQUID HIGH-BOILING HYDROCARBON MATERIAL INTO SAID ATOMIZING ZONE; DIRECTLY CONTACTING SAID RESULTING PRODUCTS OF CONVERSION FROM SAID FIRST CONVERSION ZONE AND SAID LIQUID HIGH-BOILING HYDROCARBON MATERIAL IN SAID ATOMIZING ZONE, THEREBY VAPORIZING A PORTION, ATOMIZING A REMAINING PORTION AND HEATING TO CONVERSION TEMPERATURE SAID HIGH-BOILING HYDROCARBON MATERIAL, AND QUENCHING SAID RESULTING PRODUCTS OF CONVERSION FROM SAID FIRST CONVERSION ZONE BELOW CONVERSION TEMPERATURE; DIRECTLY PASSING A RESULTING MIXTURE OF VAPORS AND ATOMIZED HIGH-BOILING HYDROCARBON MATERIALS INTO A SECOND CONVERSION ZONE AND THEREIN THERMALLY CONVERTING SAID HIGH-BOILING MATERIALS AT A TEMPERATURE OF FROM 950 TO 1450* F., A PRESSURE OF FROM 5 TO 40 POUNDS PER SQUARE INCH ABSOLUTE AND A CONTACT TIME OF FROM 0.2 TO 3.5 SECONDS; AND WITHDRAWING RESULTING VAPORS AND ATOMIZED HIGH-BOILING HYDROCARBON MATERIALS FROM SAID SECOND CONVERSION ZONE AND DIRECTLY CONTACTING SAME WITH A QUENCH MEDIUM, THERERBY QUENCHING TO A TEMPERATURE BELOW 900* F.